➙Is your building still using more nergy than it should be? A hidden leak in your envelope could
be the culprit.

Cracks and gaps aren’t just an opportunity for wind-driven weather to infiltrate your building, they’re also an easy
conduit for unconditioned air to enter
and for conditioned air to leave, wasting
heating and cooling dollars. Examine
your envelope with these tips to ensure
tightness.

A Compromised EnvelopeAffects Efficiency

“Air leakage is one of the major cul-prits when it comes to efficiency in build-ings,” notes John Chamberlin, Directorof Business Development for Sto Corp, abuilding envelope and coating provider.“When you have unwanted air move-ment through the building, there’s coldair coming in and warm air getting outwhen you don’t want it to. Meanwhile,your HVAC or heater is trying to addressTo make matters worse, air infiltrationcan easily lead to moisture infiltration,whether the air carries vapor with itor weather squeezes through the samespaces air does, adds James Hodgson,General Manager of Premier SIPs, astructural insulated panels manufactur-er. This can further lower your building’senergy efficiency and leave it vulnerableto mold and structural damage.

“This typically happens in and around
the actual envelope, meaning you either
have issues in the openings where things
fit incorrectly or there’s settling with
the foundation,” Hodgson explains.
“Often, windows are either forced in or
loosely applied when they’re installed.
That starts to compromise areas where
moisture can enter. Natural movement

Inspect for Issues

If you think your envelope might be
leaking, start by examining openings,
Hodgson recommends. Details are much
more vulnerable to air and moisture
intrusion than the larger, uninterrupted
areas of the envelope, Chamberlin adds,
so paying attention to cracks, joints,
seams and penetrations is important.

“Look for cracks on the envelope. Youcan often see where sheet rock is startingto crack on a paint line, especially on anexterior wall – that might be an indicatorthat there’s settling that is compromis-ing a joint area,” adds Hodgson. “On theceiling, if you’ve got exposed trusses, youcan see whether there’s any water dam-age on the underside of the roof. Take agood look at the windows and make surethey’re sealed correctly with caulk andthey aren’t bowed – sometimes if settlingoccurs, a window will bow and createsthe potential for moisture intrusion.”Depending on your building type, youmight also spot efflorescence (a chalkysubstance) on brick or cracks in a stonefacade that would indicate degradationfrom moisture leakage, Chamberlin says.A building with an EIFS or stucco systemmay see the outlines of metal fastenersand anchors appearing on the exterior,an indicator that the envelope wasn’tsealed properly.

“The studs act as a conductor for theheat, and when they interact with wateror cold, the thermal bridging causesa different weathering pattern on theexterior,” Chamberlin explains. “In somecases you can actually see them with thenaked eye. That’s usually a good sign thatthere’s drafting.”This can be spotted early with aninfrared camera, Chamberlin adds. Thistool can also detect hot and cold spotsand areas with moving air to help users

“Check outlets for air movement. If you
open up one of the boxes you can often
feel air moving in the walls,” Hodgson
says. “If you can do a blower door test, it
will indicate how tight your building is. If
you can’t, you can literally put a candle in
front of an opening and see whether air
is moving.”

Investigate Repair Strategies

Once you’ve discovered the source
of the problem, you can start weighing
potential fixes. A window with an aging
seal can probably be fixed with a little
caulk, for example.

“Any where there’s an opening, chancesare you’ll need some form of sealant,”Hodgson notes. “If you’re going tochange out windows, check the flash-ing as well and make sure that’s in goodcondition. An open space like a ceilingarea could potentially benefit from rigidIf you have the budget for a larger ret-rofit, adding a liquid-applied air barrierand then repainting or recladding on topof it can help keep out air and moisture,Chamberlin suggests.